Prescription Drug Coverage
Learn about Medicare Part D, which is included in many Medicare Advantage plans, and how it covers prescription medications, as well as the coverage gap or "donut hole."

The Medicare Prescription Drug Program, also known as Medicare Part D, is a voluntary program that provides outpatient prescription drug coverage to Medicare beneficiaries. Part D plans are offered by private insurance companies approved by Medicare, and they help cover the cost of prescription medications. Here are some key details about the Medicare Prescription Drug Program:
Enrollment: You can enroll in a Part D plan when you first become eligible for Medicare during your Initial Enrollment Period (IEP), or you can sign up during the Annual Election Period (AEP), which runs from October 15 to December 7 each year. You may also qualify for a Special Enrollment Period (SEP) under certain circumstances, such as moving out of your plan's service area or losing other creditable prescription drug coverage.
Standalone Part D vs. Medicare Advantage with Prescription Drug Coverage (MAPD): Part D plans can be standalone, meaning they only provide prescription drug coverage and can be paired with Original Medicare (Parts A and B) or a Medicare Advantage plan without drug coverage. Alternatively, many Medicare Advantage plans include Part D coverage, known as Medicare Advantage Prescription Drug (MAPD) plans.
Premiums: Part D plans charge a monthly premium, which varies depending on the specific plan and its coverage. If your income exceeds a certain threshold, you may also pay an additional Income-Related Monthly Adjustment Amount (IRMAA) for your Part D coverage.
Formulary: Each Part D plan has a formulary, which is a list of covered medications. Formularies are divided into tiers, with each tier representing a different cost-sharing level. Lower tiers typically include generic medications with lower copayments, while higher tiers contain brand-name or specialty drugs with higher copayments or coinsurance.
Coverage Phases: Part D coverage typically consists of four phases:
Deductible Phase: You pay the full cost of your medications until you reach your plan's deductible (if applicable). Some plans have no deductible or waive the deductible for certain tiers.
Initial Coverage Phase: After meeting the deductible, you pay a copayment or coinsurance for each prescription, and your plan covers the remaining cost. This phase continues until your total drug costs (what you and your plan have paid) reach a predetermined limit.
Coverage Gap (Donut Hole): Once you reach the initial coverage limit, you enter the coverage gap. During this phase, you pay a higher percentage of your medication costs until you reach the out-of-pocket spending threshold.
Catastrophic Coverage: After surpassing the out-of-pocket spending threshold, you enter the catastrophic coverage phase. In this phase, you pay a significantly reduced copayment or coinsurance for your medications, and the plan covers the majority of the costs.
Extra Help: Low-income beneficiaries may qualify for Extra Help, a program that provides financial assistance with Part D premiums, deductibles, copayments, and coinsurance.
Late Enrollment Penalty: If you do not enroll in a Part D plan when you are first eligible and do not have creditable prescription drug coverage elsewhere, you may face a late enrollment penalty. This penalty is added to your Part D premium for as long as you have Medicare drug coverage.
When choosing a Part D plan, it's essential to compare multiple options and review each plan's formulary, premiums, deductibles, and cost-sharing structure. Consider your medication needs and budget to select a plan that best suits your requirements.